Method of making tire-covers.



.l. T. JOHNSON & F. G. MASON.

METHOD OF MAKING TIRE COVERS.

APPLICATION FILED MAR. 1. 1913.

1,142,042. Patnted June 8, 1915.

6 WITNESSES I INVENTOVS f W s rens;

I AUSTRALI amps cinema mews 1" f Specification of 1 App itationmed arh 7,1913. I, Serial No. 752,557,;-

: To rill'wl om, am (17/ concern "of the King of Great Britain, residing at Methods of Making Tire Covers','ofEWhich certain new and'useful Improvements in the following is a speci fication'.

This invention relates to an improvedf" method of n'ianufacturing pneumatic-tire covers described? in? our Patent Number 1,062,401, whcrel'-)y thefs't-ructure will be}; stronger and more efficient than covers now in use.

Pneumatic tire covers are nojw built up of a series of strips of canvaswith or without interlying rubber sheets arranged longitudinally about the tire, but it has been found very diilicult to cause the superposed sheets of canvas to perfectly adhere in the curved and annular form. It has been further suggested that a tire cover be made with a strip or strips of canvas coate with a semielastic composition which wh1le in a tacky condition is wound under tension in successive convolutions upon a rim or form and subsequently vulcanized to cause the convolutions to combine together in a solid mass. In practice however, the method has been found to be defective owing to the unequal adhesion at the edges of sides of the spirally wound strip or strips.

In a pneumatic tire cover it is of prime importance that the adhesion of the materials composing it shall be as nearly perfect as possible for the purpose of withstanding, as one homogeneous whole, the excessive strains to which a tire is subjected when in use. In devising our invention we have paid special attention to obtaining the best adhesion possible of the parts forming a tire cover, and have illustrated the invention in the accompanying drawings, in WlllCll Figure l is a plan showing the ail-rangement of parts used in forming a cover. Fig. 2 shows in perspective view part of a pneumatic tire with the arrangement of strips in accordance with the invention. Fig. 3 is an enlarged sectional elevation on the line 11 of Fig. 1, showing the layers of rubber and canvas above and below the beads before the tire is finally formed. Fig. 4 is an enlarged view of part section, on the line 22 of Fig.

1, showing two strips and attached rubbers.

't known that s ams Ti ioams Jo'rrN- sols and'FluctuationGannon Masoujsub ects the construction of, a pneumatic'tire .co'vera ccording to this invention, we first, .cutslrort strips of a Woven ,fabric o'utof a sheet of materia'lf'It is preferabl'eto' cut (Taulfield;Victoria, anaemia, have inv'ented'f i I thestripsj"on the bias thatis "Ltosay,

neitheralong the woof the 'weffljbut across each. Each of thestrips' 5' isfaeed onfboth sides with a thinsheet ofrubbe'r, 61

Wh ay mp y cover the atria" so that th'elatter will be containedwithin a rubber envelop. The strips. are laiduip'on the head "used incons'tructionof the tire, ,'an(lfor1ned the shape 'and about the size of the innei tube of the tire being'm'ad'e, at an about 45 mm the faceoit' the wheel and consequently when a second layer is laid on the first but from the other direction, such first and second layers will be at right angles to each other. Each of the strips 5 overlaps its neighbor when along each of its edges a. gutter is formed which if left unfilled will, owing to the number so constituted, be a source of weakness in the cover by preventing the proper vulcanization of the parts into a solid mass.

To insure the best results in the construction of a tire cover and from the subsequent vulcanizing process we may cause the rubber facings of the strips 5 to overlap on both edges for a distance sui icient, when the strips are laid, to come over the strips beneath and above and to overlap each just enough to fill the gutters formed by the contiguous strips. This arrangement is shown in Fig. 1 of the drawings.

In making a cover, the strips are laid overlapping each other across the former or mold from the right to left and then a second series of overlapping strips is laid at right angles to the first lot from left to right. The number of layers used will depend upon the class of tire required; for very heavy tires six or eight layers may be used, while for a light service as few as two may be suflicient. For ordinary tires four layers will sutiice, two being placed under the annular beads 7 and two over the same.

Before commencing to lay the strips on the head former or'mold we place upon the latter arubber sheet which entirely covers the same. Upon the rubber sheet 8 we then lay the rubber incased strips in the manner explained.

By using the strips out to a length only strips are rolled in the suilicient to cross the former diagonally from bead t0 bead we can be assured of better adhesion of the same when the tire cover is subjected in a press to the process of vulcanization, The fabric being entirely enveloped in rubber will not be visible andzthe rubber surfaces, the sheet 8 and the rubber 9 will have little-difl'iculty in combining into an integral mass capable ofwithstandingbeen put in position the whole is placed. in a heated press for the purpose of vulcaniza-V tion.

Fig. 3' is intended torepresent an eXag gerated transverse section of a cover wherein is clearly depicted the manner in which the strips overlap, the rubber being shown crosshatched in the solid form after vulcanization the better to distinguish the same from the strips 5 shown in heavylines.

Having now described our invention what we claim as new and desire to secure by Letters Patent is e The improved method of making a pneumatic tire cover which consists in the utilization of short strips of woven fabric faced on both sides with rubber so as to envelop a strip and that are then laid in series diagonally upon an annular former or mold, upon which is a rubber sheet, in such a way that each strip of a series overlaps the next strip of the same series, then superposing upon the first series another series of strips at right angles thereto, retaining the whole 7 with annular beads, and vulcanizing the same, with a rubber tread in a press or form,

as herein eXplamed.

Signed at Melbourne, Victoria, this 20th day of May 1912, in the presence of two witnesses.

JOHN THOMAS JOHNSON. FREDERICK e. MASON.

- Witnesses: v P. M. NEWTON,

M. ALLAN. 

